TOKYO (Reuters) - Toshiba Corp said on Friday it would not be able to complete an $18 billion deal to sell its prized chip unit by an agreed deadline at the end of March, as it had not received anti-monopoly approval from China.

Failure to meet the deadline gives Toshiba the option of walking away from the sale of the world's No. 2 producer of NAND chips without penalty - a move that some investors have urged it to consider.

But the company said in a statement that it still plans to sell the unit, aiming to finalize the deal as soon as possible.